Thrust-vectoring devices for jet engines



Dec. 22, 1970 n. P. 1.... coLoMBANl Erm. 3,548,598

THRUST-VECTORING DEVICES FOR JET ENGINES Filed Illy 9. 1968 FigJ United States Patent O 3,548,598 THRUST-VECTORING DEVICES FOR JET ENGINES Don Pierre Louis Jean Colombani, Latresne, and Adolphe Otton Gontier Ernst, Lege, France, assignors to Societe Nationale dEtude et de Construction de Moteurs dAviation, Paris, France Filed May 9, 1968, Ser. No. 727,818 Claims priority, application lrance, May, 18, 1967, 1 6 83 Int. Cl. B63!! 25/46; B64c 15/10; FllZk 1/20 U.S. Cl. 60-231 5 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a jet propulsion nozzle equipped with jet deflecting means operating by selective injection into the nozzle of one or more auxiliary jets through orifices opening more or less transversely on to said nozzle and supplied with compressed gas from a generator fitted aside said nozzle and generally using either a powder or liquid fuel.

It is well known to employ Stich thrust-vectoring techniques in a jet engine to produce controlling or stabilizing couples acting on the vehicle being propelled, and it is equally well known that fundamentally this is a very delicate operation and one which requires a very high degree of precision, something which can only be obtained through precise determination of the extent and duration of the deflection. It is therefore desirable to have the supply of gas coming from a gas generator which operates at virtually constant pressure, so that the said amplitude and duration of jet deflection are not affected by disturbing parameters which would otherwise have to be detected and measured for the purposes of effecting appropriate correction.

However, the requisite supply of gas for the production of auxiliary dellecting jets (which supply must be variable to accord with the amplitude and duration of the desired deflection) must be reliably assured by the generator at any instant and for the whole of the requisite period. It is therefore necessary that the amount of gas supplied should constitute only a fraction of the total capacity of the generator, and that furthermore the time during which it is supplied should likewise only be a fraction of the total time of supply which the generator is capable of. In other words, in order to satisfy all possible requirements in terms of gas supply for thrust-vectoring purposes, the generator must be over designed to possess an excess capacity both as regards total amount of gas available and time for which the supply can be maintained.

This gives rise to difficulties as regards maintaining constant pressure combustion in the generator, notwithstanding the transitory and variable character of the flow rate and period of supply of the gas.

The invention relates to an improvement to such a device with the object to maintaining virtually constant ICC combustion pressure inside the gas generator, numerous advantages resulting from this improvement.

The invention may be carried into practice in various ways, but a preferred practical embodiment and modification of thrust-vectoring device according thereto will now be described by way of example with reference to the drawing, in which:

FIG. l is a schematic view of the preferred embodiment of device in accordance with the invention; and

FIG. 2 is a longitudinal section of a variant embodiment.

FIG. l illustrates a primary nozzle 1 of a jet propulsion engine, for example a rocket engine, with auxiliary transverse jets 2 each in the form of a slot, one of said jets being shown supplied with compressed gas from a suitable autonomous generator 3, via a piping system 4 which includes a valve 5 controlled by a servomotor jack 6.

As long as the valve 5 remains closed, there is no supply of gas to said auxiliary jet 2 and the main jet issuing from the nozzle 1 undergoes no deflection. On the other hand, when the jack 6 opens the valve 5, the gas generator 3 communicates with this auxiliary jet 2 through the piping system 4; since gas is now being supplied to the jet 2, a transverse dellecting action is produced in the primary nozzle l and the main jet issuing therefrom is deflected (vectored) away in the opposite direction. It is clear that the amplitude of the deflection will be a function of the extent to which the valve 5 is opened and that this deflection will persist as long as the valve 5 remains open.

In accordance with the invention, the vectoring device above-described is improved in the following ways:

The gas generator 3 is associated with a second piping system 7 which terminates in a variable area discharge orice 8, the variation being produced by the axial displacement of a central plug 9. The combination of the orifice 8 and of the mobile central plug 9 amounts to a secondary variable-area nozzle adapted, in accordance with the expansion ratio, in order to produce a secondary jet so directed as to contribute to the propulsivc thrust.

The axial position of the central plug 9 is determined by a hydraulic jack 10 which, in the example illustrated, is of the single-acting type; its piston 11, connected to the central plug 9 through the piston rod 12, is loaded on one side by a return spring 13 which biases the central plug 9 into a posiiton in which it closes olf the discharge orifice 8 or reduces it at least to a minimum cross-section, and is acted on at its other side by an auxiliary fluid (oil for example) fed through a servovalve 14 operating in an on/off manner or in a continuously variable manner.

The control of this servovalve is effected by means of a discriminator 15 which compares a predetermined reference pressure with the instantaneous pressure prevailing in the gas generator 3, the instantaneous pressure being detected by a suitable pressure-detecting device 16. The discriminator 1S may be designed as a conventional electronic trigger stage. As soon as the pressure in the generator 3 reaches the predetermined threshold level, the discriminator 15, on receipt of an electrical signal from the pressure detector 16, opens the servovalve 14 and hydraulic pressure is then applied to the bottom face of the piston 11 controlling the plug 9 associated with the discharge orice 8. During a vectoring operation` i.e. when the valve 5 is opened to tap off gas from the generator 3 through the piping system 4 feeding the auxiliary 2, the servovalve 14 exhausts the oil beneath the piston 11 so that the latter can be returned under the action of the spring 13 to close olf the secondary nozzle 8, 9.

The assembly above described acts as a regulator to maintain the pressure in the gas generator 3 virtually constant by opening or closing the secondary nozzle 8, 9, in accordance with whether the generator pressure is tending to rise or to fall.

FIG. 2 illustrates a variant embodiment of the system used to control the central plug 9. This element is in this embodiment lixed to a core 12a acting as the moving plunger of a solenoid indicated at 17, the energising cir* cuit 18 of which is controlled by a suitable relay asso ciated with the discriminator 15.

The gas leaving the generator 3 passes, as before, through the piping system 7, which is connected to a damping chamber 19 opening out through the discharge orifice 8, inside which chamber are located the solenoids 12a and 17 controlling the central plug 9 and the return spring 13.

What is claimed is:

l. A thrust-vectoring device comprising a primary jet propulsion nozzle designed for discharging a main jet, an autonomous pressure gas generator fitted aside said nozzle, and auxiliary jet means selectively connectable to said generator to be selectively supplied with pressure gas therefrom and opening into said primary nozzle to deflect said main jet,` wherein the improvement comprises:

a secondary variable-area jet propulsion nozzle connected to said generator in parallel with said auxiliary jet means,

means for varying the area of said secondary nozzle,

means for detecting gas pressure obtaining in said generator, and

regulator means for bringing said nozzle area varying means under the control of said pressure detecting 4 means, said regulator means operating in the sense of an increase in nozzle area upon detection of gas pressure higher than a reference value and inversely, whereby said gas pressure is kept substantially at said reference value.

2. Device as claimed in claim 1, wherein said regulator means comprise a discriminator designed for comparing said reference pressure value with the gas pressure value detected by said pressure detecting means and for delivering a nozzle-area varying signal whenever said gas pressure value departs from said reference pressure value.

3. Device as claimed in claim 1, wherein said secondary variable-area nozzle is resiliently biased to nozzle constriction.

4. Device as claimed in claim 1, wherein said secondary nozzle is an adjustable plug nozzle.

S. Device as claimed in claim 1, wherein said primary and secondary nozzles have substantially parallel axes.

References Cited UNITED STATES PATENTS 3,132,476 5/1964 Conrad 60-23l(X) 3,232,537 2/1966 Jaramillo et al. 60-231(X) 3,308,846 3/1967 Yuile 137-492.5(X) 3,325,103 6/1967 Abbott 239-265.23(X) ALLAN D. HERRMANN, Primary Examiner U.S. Cl. XR. 

